Caltech Micromachining Laboratory
Micromachined High-Aspect-Ratio Parylene Beam and Its Application Low-Frequency Seismometer
Project Abstract
A new microfabrication technology for high-aspect-ratio Parylene
structure is developed for soft spring applications and applied to
in-plane seismometer, which covers low frequency (< 1Hz) and small
acceleration range. Parylene beams having 10-40mm wide and an
aspect ratio of 10-30 were successfully fabricated. Since Parylene
has a small Young’s modulus and is non-brittle material, high-aspect-ratio
robust beam having spring constant on the order of 1x10-3 N/m was
realized. A prototype capacitive seismometer was also made, and its
resonant frequency and noise spectral density was respectively measured
to be 37Hz and 45mg/(Hz)1/2. Since the Brownian noise is only 25ng/(Hz)1/2,
seismometer having much lower noise floor may become feasible using this
new technology.
References
Y. Suzuki and Y.C. Tai, "Micromachined High-Aspect-Ratio Parylene Beam and Its Application to Low-Frequency Seismometer," Proceedings,
The Sixteenth IEEE International Conference on Micro Electro Mechanical Systems (MEMS '03), Kyoto, Japan, Jan. 19-23, pp. 486-489, (2003).
Involved Personnel
Yuji Suzuki and Yu-Chong Tai